A to Z
Data &
Forms &
News &
Licensing &
Rules &
Public Health
Understanding Cancer Clusters

A cancer cluster is a greater than expected number of cases of a specific cancer. Cancer clusters may be suspected when people report that several family members, friends, neighbors or coworkers have been diagnosed with cancer.

Cancer Clusters: Common Cause or Chance?
CD Summary: Vol. 49, No. 14
Oregon Health Services has for years received occasional inquiries about suspected cancer clusters. The majority of subsequent investigations do not yield a common etiology because most cancer clusters occur by chance and are otherwise unrelated. This CD Summary informs readers about how we respond to a suspected cancer cluster, and the experience of others investigating such reports.

The first step in investigating a cancer cluster is to gather and document information regarding the number of cases, the population group or area involved, the time period over which cases occurred, and the suspected cause. The Oregon Health Authority has developed these report forms to collect some of this additional information:  

More Information